MDEV-4977 ./mysql-test/mysql-test-run.pl not identifying mariadb version

quote the path when using it in a regex - the path might contain wildcards (e.g. +)

mysql-test/mysql-test-run.pl

@@ -1890,7 +1890,7 @@ sub collect_mysqld_features {
 
   my @list= split '\n', $list;
   mtr_error("Could not find version of MariaDB")
-     unless shift(@list) =~ /^$exe_mysqld\s+Ver\s(\d+)\.(\d+)\.(\d+)(\S*)/;
+     unless shift(@list) =~ /^\Q$exe_mysqld\E\s+Ver\s(\d+)\.(\d+)\.(\d+)(\S*)/;
   $mysql_version_id= $1*10000 + $2*100 + $3;
   $mysql_version_extra= $4;
   mtr_report("MariaDB Version $1.$2.$3$4");